1. Technical Field
The present invention relates to a seat supporting structure in a saddle riding type vehicle in which both ends in a vehicle width direction of a seat are movably supported by a rear frame of a body frame.
2. Background Art
Conventionally, a seat of a motorcycle, which is an example of a saddle riding type vehicle, adopts a structure in which a cushion material consisting of urethane foam or the like is placed on a bottom plate of plastics and the cushion material is covered with a skin. In order to fix this seat to a body frame of the motorcycle, a front end of the bottom plate in a front-rear direction (longitudinal direction) of the vehicle is engaged with the rear of a fuel tank and the rear end of the bottom plate is fastened by bolts. In addition, in the center of the seat in the front-rear direction of the vehicle, a leg, which is integrally formed to protrude downward from the bottom plate, is movably supported by the rear frame, such that the body frame can support the weight of a rider.
On the other hand, as a motorcycle, there is a so-called motocrosser for competing for speed of running off-roads. A two-cycle engine is often used in this type of motorcycle in order to reduce the weight of the vehicle. In the motocrosser mounted with the two-cycle engine, a kick type starter is used and a starter motor is not used.
The inventors consider mounting a four-cycle engine on the motocrosser and equipping the motocrosser with the starter motor.
Here, in equipping the motocrosser with the starter motor,it is preferable to mount a battery for supplying power to the starter motor below the seat. However, this causes a problem in that a bottom plate of the seat hits the battery when the seat bends downward largely.
The bottom plate of the seat bends largely, for example, when the vehicle jumps and makes landing and the weight of the rider is applied to the seat as an impact load. In other words, a large load is applied to the seat, whereby a leg protrudingly provided on the bottom plate inclines to topple to the inside of the vehicle, and the center of the bottom plate in a width direction of the vehicle curves downward viewed from the front-rear direction. Thus, the bottom plate bends downward largely.
Note that, since the battery is a heavy object, a mounting position of the battery is restricted in bringing a center of gravity of the vehicle close to an ideal position. For example, it is difficult to mount the battery in a section other than a section below the seat, and it is not easy to mount the battery in a lower position because it is likely that the battery interferes with other components located below the seat.
The deficiency can be eliminated if a position of the seat is set high or the bottom plate is formed of metal, for example, such that the seat does not bend easily. However, if the seat is set in a higher position, a seating position of a rider becomes higher and a center of gravity at a time of riding becomes higher. The rider is given a sense of incongruity if the seat does not bend at all. In addition, the deficiency can be eliminated if the seat is formed to be reduced in thickness so as to separate the bottom plate upward from the battery. However, when this structure is adopted, since a cushion material is reduced in thickness, the rider is given a feeling unpleasant when the buttocks of the rider hit the bottom plate via the cushion material when the rider is seated.